Is this Eubranchus misakiensis?

May 25, 2002
From: Nishina Masayoshi

Dear Bill,
My wife found this animal at Echizen coast. I feel this animal is a kind of Eubranchidae. I feel that this may be Eubranchus misakiensis. I also feel my animal and the animal identified as E.misakiensis by Dave Behrens are the same.

However, this animal does not look like the animal that I posted before and you identified as E.misakiensis. Or there is another possibility that this may be E. horii Baba, 1960?

Date:4 May, 2002
Location: Echizen coast, Fukui Pref. Japan
Length: 5mm
Depth: 5m

Found and photographed by N. Chikako

The animal was found on algae (upper photo) and moved to another place for the lower photo.

Best Regards,
Nishina Masayoshi

Masayoshi, N., 2002 (May 25) Is this Eubranchus misakiensis?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Nishina & Chikako,
As you will see from the other messages I have posted today, the identity of E. misakiensis is not altogether clear. Some species are quite variable in colour and when they are described and named from only a few specimens, we often have no idea just how variable they are in colour. That is why I welcome photos even of species we already have photos of, because it gives us an opportunity to see just how variable some species can be. Of course no conclusions can be reached until anatomical studies are carried out but at least it helps us to know which species, or groups of species, are problematical, and which are not.

I am pretty sure your animal is not E. horii, because that species was described as having regularly shaped cerata, without swellings, rounded anterior foot corners, and no spots. The colour pattern consists of brown bands that runs across the head from the oral tentacles to the inside base of the rhinophores. There is also a brown streak in the dorsal midline between the first and second groups of cerata.

I am sorry that some of these animals are proving difficult to identify, but all the photos you and our other friends in Japan are sending to the Forum are very valuable in helping us to better understand the fauna, and hopefully will help us to resolve these identification problems.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (May 25). Comment on Is this Eubranchus misakiensis? by Nishina Masayoshi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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